This invention relates generally to apparatus for supporting ceramic articles to be kiln fired and, more particularly, to improvements in a superstructure for a kiln car used to support and convey articles to be kiln fired.
A variety of ceramic article supporting superstructures are known in the prior art. The most common superstructures use large slabs supported on pillars or posts with the upper surfaces of the slabs serving as the article supporting surfaces.
The usual method of constructing such a kiln car superstructure is to place a slab on top of four vertical pillars positioned such that the slab is supported at its corners. By placing four more vertical pillars on top of the first slab substantially in line with the first four pillars, a second slab is supported thereabove. By repeating this process, a desired number of ware supporting surfaces or decks are constructed on the kiln car.
Slabs may be supported and joined across their width and length to form a superstructure that matches the dimensions of a particular user's kiln car. This stacked type of kiln car superstructure is disclosed, for example, in U.S. Pat. No. 1,665,631 and U.S. Pat. No. 2,879,577. Even though the slabs are oftentimes cemented to the posts, stacked superstructures tend to lack mechanical stability and rigidity. The concentration of the accumulated weight of the upper shelves and pillars at the corners of the lower shelves coupled with thermal stresses encountered during kiln firing also tends to cause cracking in this area of the lower shelves. Further, if a shelf must be removed for any reason, e.g., cracked corners, it is necessary to tear down the shelves and pillars above the one to be removed, frequently leading to the disassembly of the entire structure.
To improve the superstructure formed by stacked pillars and slabs, a unitary pillar or post provided with projections along the post at locations. where shelves are to be supported is disclosed in U.S. Pat. No. 1,969,126. This unitary post construction does eliminate the concentration of the accumulated weight of the upper posts and shelves at the corners of the lower shelves as found in the stacked arrangement. However, the unitary posts are not readily adaptable to the construction of varying height superstructures and the shelves are still supported only at the corners. Also, even though the unitary posts are pinned at a top-most shelf or cover, the resulting structure is not as stable or rigid as desirable for a kiln car superstructure.
It is, thus, apparent that a need exists for an improved superstructure for a kiln car which provides versatility, stability and rigidity for supporting articles and article carriers during kiln firing.